Today we are still lacking reliable data on the distribution of the three velocity components (Ux, Uy, Uz) in a free spatial water flow. Published data on the measurement of velocities at points of a flow performed with the help of impeller current meters concern only the time-averaged longitudinal velocity (Ūx); filming of indicators moving in a flow yields instantaneous velocities only in the plane of the width of the light ray and makes it possible to evaluate the instantaneous longitudinal (Ux) and vertical (Uy) components of the flow velocity after appropriate processing of the video frames [1, 2]. The velocity structure of a turbulent spatial flow can be characterized completely only in the case of simultaneous evaluation of all the three components of the flow velocity with respect to the value and the direction, the combination of which gives a general characteristic of the motion of the liquid and its partial manifestations typical for turbuleut flow in open watercourses. The latter circumstance is especially important for solving complex problems of river hydraulics and channel processes, for example, the transfer of silt and the conditions of flow formation in side water channels.